Lubricant 

     Lubricant is a class of oils used to reduce the friction, heat, and wear between mechanical components that are in contact with each other. Lubricating oil is used in motorized vehicles, where it is known specifically as motor oil and transmission fluid. A good lubricant generally possesses the following characteristics:
• A high boiling point and low freezing point (in order to stay liquid within a wide range of temperature)
• A high viscosity index
• Thermal stability